import java.util.HashSet;

public class Test03 {
    public static void main(String[] args) {
        Student s1=new Student("zhangsan",23);
        Student s2=new Student("lisi",24);
        Student s3=new Student("wnagwu",24);
        Student s4=new Student("zhangsan",23);
        HashSet<Student> hs=new HashSet<>();
        System.out.println(hs.add(s1));
        System.out.println(hs.add(s2));
        System.out.println(hs.add(s3));
        System.out.println(hs.add(s4));
        System.out.println(hs);
    }
}
